配置高抗站的海上风电长距离海缆送出继电保护分析

Analysis of Relay Protection for Offshore Wind Power Long-Distance Submarine Cable Transmission with High Resistance Station

目前中国长距离海上风电主要采用高压交流送出方式,并增设中端补偿高压电抗补偿站。为解决配置海上高抗站的海上风电长距离海缆送出相关保护配置问题,选取典型案例,分析继电保护配置方案与动作特性,对海缆范围故障保护可靠性进行研究,分析海上高抗取不同测点电压对电容电流补偿计算的影响,并通过仿真验证线路保护采集海上高抗侧电压计算差动补偿电流的必要性。仿真结果表明:当发生区内线路故障时,与采集高抗侧实际电压相比,取线路侧电压代替高抗电压对保护装置计算的补偿电流具有一定影响。为减少差动补偿电流计算误差,纵联差动保护应采集海上高抗站电压来计算差动补偿电流,再计算经补偿后的差动电流,实现对电容和电抗电流的修正。

China’s current long-distance offshore wind power mainly follows a high-voltage AC transmission mode with an additional mid-range high-resistance compensation station.With regard to the problem about protection configuration for offshore wind power long-distance submarine cable transmission with the high resistance station,the relay protection configuration scheme and action logic are analyzed with a typical case.The reliability of range fault protection for submarine cables is studied,and then the impact of voltages at different measurement points taken by the offshore high resistance station on the calculation of capacitive current compensation is analyzed.In addition,the necessity of collecting the voltage on the offshore high-resistance side to calculate the differential compensation current is verified by simulation.The simulation results show that for the fault within the protection range,compared with collecting the actual voltage on the high-resistance side,taking the line-side voltage instead has a certain impact on the compensation current calculated by the protection device.To reduce the error in calculating the differential compensation current,the protection device should collect the voltage of the high-resistance station to calculate the differential compensation current and then work out the differential current after compensation to correct capacitive and reactive current.